Bicycle having pedal drive, and pedal drive

ABSTRACT

Bicycle ( 1 ), comprising a first frame part ( 2 ) connected to a second frame part ( 13 ). The second frame part ( 13 ) is provided with a drive ( 14 ), comprising a crankshaft ( 16 ) carrying a driving gear blade ( 19 ) and a rear axle ( 17 ) carrying a driven gear blade ( 23 ). The bicylce ( 1 ) has as a particular feature that the drive ( 14 ) further comprises a gear hub ( 18 ) carrying a first, input gear blade ( 27 ) and a second, output gear blade ( 28 ), which gear hub ( 18 ) is mounted on the second frame part ( 13 ) at a distance from the rear axle ( 17 ).

The invention relates to a bicycle, comprising a first frame partconnected to a second frame part, which second frame part is providedwith a drive, comprising a crankshaft carrying a driving gear blade anda rear axle carrying a driven gear blade and a gear mechanism forsetting the transmission ratio between the crankshaft and the rear axle.

Such bicycle is known from EP 0 505 598. EP0 505 598 describes abicycle, in particular suitable for adults, whose frame has a compactconstruction, as a result of which the bicycle occupies little spacewhen not used. In the known bicycle, the gear mechanism is comprisedwith a free, rigid axle carrying a first, input gear blade or pinionthat is coupled to the driving gear blade and which rigid axle furthercarries a second, output gear blade or crown wheel that is coupled via aderailleur to the rear axle carrying a number of drivable gear blades.In the known bicycle, the free rigid axle of the gear mechanism providesfor a fixed transmission ratio between the input gear blade and theoutput gear blade, enabling a fixed reduction between the crankshaft andthe rear axle. The derailleur is used to set the transmission ratiobetween the crankshaft and the rear axle.

A drawback of the known bicycle is that the derailleur mechanismoccupies relatively much space. In particular, at the extremetransmission ratio, the maximally allowable obliquity of the chainbetween the gear blades of the free axle and the rear axle defines arelatively large minimal distance between the free axle and the rearaxle. Further, the derailleur mechanism requires relatively muchmaintenance and the reliability in operation of the derailleurmechanism, when maintained insufficiently, is relatively low.

U.S. Pat. No. 3,979,136 also describes a foldable bicycle having a gearmechanism comprising a fixed, rigid axle carrying a gear mechanismproviding for a fixed transmission ratio enabling a reduction betweenthe crankshaft and the rear axle. A three speed settable hub is mountedin the rear wheel to set the transmission ratio between the crankshaftand the rear wheel.

The object of the invention is to provide a bicycle of the typementioned in the preamble, in particular a compact bicycle having wheelsof a relatively small diameter, which bicycle does not have theabove-mentioned drawbacks.

To that end, a bicycle according to the invention is characterized inthat the gear mechanism comprises a gear hub having a settabletransmission ratio carrying a first, input gear blade coupled to thedriving gear blade of the crankshaft and a second, output gear bladecoupled to the driven gear blade of the rear axle, such that thetransmission ratio between the first, input gear blade and the second,output gear blade can be set, which gear hub is mounted on the secondframe part at a distance from the rear axle.

Through the use of the gear hub it is effected that the drive can be ofa more compact design, while the reliability in operation can beincreased and the maintenance can be limited. Moreover, the rear axlecan now be constructed with only one gear wheel, so that a simpler rearaxle can be used. It is further achieved that in the drive, a gear hubcan be used that is normally accommodated in a rear wheel of a largediameter, that is, a diameter of 26 inch (66.04 cm) or 28 inch (71.12cm). Since such gear hubs are already mass-produced and can be obtainedrelatively cheap, this reduces the costs of the bicycle considerably.

In another embodiment, a bicycle according to the invention ischaracterized in that the first frame part is connected to the secondframe part for pivoting relative to a pivotal axis, such that the frameparts can pivot between an operating position of the bicycle in whichthe wheels of the bicycle are substantially in line, and a foldedposition of the bicycle in which the wheels are substantially locatedside by side.

Preferably, the pivotal axis extends substantially vertically and thefirst frame part carries a saddle, while the second frame part comprisesa single supporting arm for the rear axle. It is thus achieved that infolded condition, the bicycle occupies little space, while the pedaldrive is located entirely within the second frame part. This lastfacilitates the pivoting action between the operating position and thefolded position and simplifies the construction of the bicycle.

It is observed that in this context, the expression that the gear hub islocated at a distance from the rear axle should at least be understoodto mean that the center line of the gear hub does not coincide with thecenter line of the rear axle.

The invention also relates to a pedal drive.

These and further advantages of the invention will be specified withreference to an exemplary embodiment of a bicycle according to theinvention shown in the accompanying drawings. In these drawings:

FIG. 1 is a schematic side elevation of a foldable bicycle with pedaldrive in operating condition;

FIG. 2 is a schematic side elevation of the bicycle of FIG. 1 in foldedcondition,

FIG. 3 is a partially cutaway, schematic top plan view of a pedal driveof the bicycle of FIG. 1; and

FIG. 4 is a schematic side elevation of the drive of FIG. 3.

It is observed that the Figures are only schematic representations of apreferred embodiment of the invention. In the Figures, identical orcorresponding parts have been designated by the same reference numerals.

FIG. 1 shows a foldable bicycle 1 in operating condition. The bicycle 1is suitable for adults and has a compact construction. The bicycle 1 hasa first frame part 2 with a steering head 3. The steering head 3 carriesa single supporting arm 4 in which a front wheel 25B is included. Bymeans of a handlebar 6, the supporting arm 4 can be pivoted relative tothe first frame part 2 about a substantially vertical pivotal axis 7.The first frame part 2 further comprises a saddle arm 6 carrying asaddle 9. The saddle arm 8 is connected to the first frame part 2 so asto be pivotable relative to a substantially horizontal pivotal axis 10.

On a side remote from the steering head 3, the first frame part 2 isconnected to a second frame part 13 for pivoting relative to asubstantially vertical pivotal axis 12 by means of a lockable hinge 11.In the operating position shown, the hinge 11 is locked by means of alocking mechanism not shown. Further, spring means, not shown, may beaccommodated adjacent the hinge 11, which spring means enable a springmovement of the frame parts 2, 13 relative to each other.

The second frame part 13 comprises a pedal drive globally indicated byreference numeral 14. The pedal drive 14 is at least partiallyintegrated with a single supporting arm 26. The supporting arm 26 andthe pedal drive 14 are surrounded by a slender housing 15. The housing15 protects the pedal drive 14 from entering dirt and also prevents theclothes of a rider of the bicycle from possibly being fouled by parts ofthe pedal drive 14. Further, the slender housing provides the bicyclewith an open appearance.

The supporting arm 26 carries a rear wheel 25A. The diameter of the rearwheel 25A is relatively small, at least considerably smaller than 26inch (66.04 cm), preferably smaller than 22 inch (55.88 cm), inparticular about 20 (50.8 cm) or 16 inch (40.0 cm). It is observed thatthe diameters of the wheels 25A, 25B are stated here in inches, becausethis is conventional in the field of bicycles, and that 1 inchcorresponds to 2.54 cm.

The bicycle 1 can be folded in for reducing the space occupied when thebicycle 1 is not used. This enables for instance placing the bicycle 1into a trunk of a motorcar, or putting it up or storing it in a smallspace, such as a cupboard. To illustrate this, the bicycle 1 is shown infolded-in position in FIG. 2.

The construction of the bicycle 1 is described in NL-A-1006637.

With reference to FIGS. 3 and 4, the pedal drive 14 is shown thereinwithout the housing 15. The pedal drive 14 comprises a crankshaft 16, arear axle 17 and a gear hub 13. The crankshaft 16 carries a driving gearblade 19 and is provided, adjacent opposite ends 34, 35 thereof, withcranks 20 that each carry one pedal 22 adjacent their free ends 21 (FIG.1). The crankshaft 16, the cranks 20 and the pedals 22 are constructedin the conventional manner and are conventionally mounted on the secondframe part 13 for rotation.

The rear axle 17 carries a driven gear blade 23. The rear axle 17further carries the rear wheel 25A, via a hub 24. By means of the singlesupporting arm 26, the rear axle 17 is attached to the second frame part13. Although by means of a single supporting arm 26, the space occupiedby the bicycle 1 in folded condition can be reduced substantially, it isobserved that the rear axle 17 may also be conventionally attached tothe frame 1 two-sidedly by a rear fork.

The second frame part 13 further comprises a gear hub 18 carrying afirst, input gear blade 27 and a second, output gear blade 28, such thata settable transmission ratio is possible between the first, input gearblade 27 of the gear hub 18 and the second, output gear blade 28 of thegear hub.

The gear hub 18 comprises a first hub part 36 carrying the first, inputgear blade 27 at an end 29 thereof, and a second hub part 37 carryingthe second, output gear blade 28 at an end 30 thereof. The hub parts 36,37 are each mounted so as to be rotatable relative to a through support38, which support 38 is fixedly connected to the second frame part 13.The hub parts 36, 37 are further coupled so as to be rotatable relativeto each other. The coupling is designed so that the transmission ratiobetween the hub parts 36, 37, i.e. the difference between the speed ofrevolution of the input hub part 36 and that of the output hub part 37,is settable. The construction and the operation of a gear hub aregenerally known and are therefore not further specified here.

Preferably, the first and second gear blades 27, 28 are each mounted onthe gear hub 18 adjacent an opposite end 29, 30 thereof. Of course, itis also possible to position the first and second gear blades 27, 28adjacent one end of the gear hub 18. By means of a first chain ortoothed belt 31, the first, input gear blade 27 of the gear hub 18 iscoupled to the driving gear blade 19 of the crankshaft 16, while bymeans of a second chain or toothed belt 32, the second, output gearblade 28 of the gear hub 18 is coupled to the driven gear blade 8 of therear axle 17. Of course, instead of a chain or toothed belt, a belt orrope may also be applied.

When the diameter of the first, input gear blade 27 is sufficientlysmaller than the diameter of the second, output gear blade 28, inparticular a gear hub 18 can be employed that is conventionally used inthe rear wheel of a bicycle having a rear wheel of a large diameter, forinstance 26 inch (66.04 cm) or 28 inch (71.12 cm). In such conventionalgear hubs, the transmission ratio between the input hub part and theoutput hub part is for instance settable between 2.7 and 5.0 (four-speedhub) or between 2.1 and 5.3 (seven-speed hub). The use of such gear hubyields a considerable cost saving during the assembly of the bicycle 1,since such gear hubs are already produced in large numbers. In thatcase, for instance the first, input gear wheel 27 can be mounted on theinput hub part 36 in the usual manner, while the second, output gearwheel 28 can be mounted on a flange of the second hub part 37, to whichflange the spokes of the rear wheel are usually attached.

Further, through the use of a gear hub 18, it is achieved that the rearaxle 17 can be one-sidedly supported by a supporting arm 26, unlike therear wheel whose gear hub is integrated with the rear axle 17, whichshould be supported on two sides.

Preferably, the diameter of the first, input gear blade 27 of the gearhub 18 is smaller than chat of the second, output gear blade 28 of thegear hub 18, as shown in FIGS. 1 and 2. Thus, a greatest possibletransmission ratio is realized between the crankshaft 16 and the rearaxle 17, i.e. one revolution of the crankshaft 16 results in a suitable,large number of revolutions of the rear axle 17.

FIG. 4 shows that the gear hub 18, viewed in side elevation of thebicycle 1, is located between an upper common tangent line B of thedriving gear blade 19 of the crankshaft 16 and the driven gear blade 23of the rear axle 17, and a lower common tangent line 0 of the drivinggear blade 19 of the crankshaft 16 and the driven gear blade 23 of therear axle 17. The effect thus achieved is that the pedal drive 14 canreadily be provided with a slender, robust housing 15. Such housing 15enhances the reliability of operation of the drive 14 considerably, inthat the ingress of dirt is impeded.

Preferably, the gear hub 18, viewed in the direction of travel of thebicycle 1, is located between the crankshaft 16 and the rear axle 17. Itis thus provided that the length of the second frame part 13 can besubstantially equal to the distance between the crankshaft 16 and therear axle 17, which reduces the space occupied by the bicycle 1.

It is observed that it is possible to fit the pedal drive 14 with springaction relative to a horizontal pivotal axis 39, for instance byconnecting the second frame part 13 with the pedal drive 14 to thebottom side of the hinge 11 so as to be pivotable as a rigid wholerelative to a horizontal pivotal axis 39, and by providing spring meansfor obstructing the pivotal movement. By incorporating the drive 14 intothe second frame part 13, the course of the chains 31, 32 can beprevented from being disturbed by the spring means springing inwards andoutwards.

When the pedal drive 14 is provided with a spring, it is preferred thatthe gear hub 18 be mounted on the second frame part 13 close to thehorizontal pivotal axis 39. It can thus be provided that during a springmovement, the moment of inertia of the second frame part 13 relative tothe pivotal axis can be smaller, which improves the springcharacteristic of the bicycle 1 compared with a situation where therelatively heavy gear hub 18 is located adjacent the rear axle 17.

By incorporating the pedal drive 14 entirely into the second frame part13 of the bicycle 1, it is further possible to move the pedal drive 14together with the second frame part 13 into and out of said foldedposition. This prevents a user's clothes from being fouled when thebicycle is being folded and unfolded, and simplifies the folding andunfolding of the bicycle

In an advantageous manner, the pedal drive 14 enclosed by the housing 15can be manufactured as a separate unit, such as a so-called subassembly.This enables the pedal drive 14 to be fitted onto the bicycle as a unit,for instance by fixing a bolt or pin joint between the drive 14 and thelower end of the hinge 11. During assembly of the bicycle, the drive 14can then be supplied as a ready-made, loose unit. Thus, the logisticsduring assembly of a bicycle in a factory can be simplifiedsubstantially, while, further, the level of knowledge required for theassembly can be lower. In addition, final assembly of the drive on thebicycle can be performed by the seller or even by the buyer, so that thebicycle can occupy less space during transport from the factory to theseller/buyer.

Further, if a defect should occur in the drive during use, it can bedisassembled and replaced as a separate unit. Thus, a bicycle having adefective drive can be repaired without the repairer requiring anyspecial knowledge or special tools. A disassembled defective drive canthen be sent to a specialist for being repaired.

By providing the drive with quick-action couplings for connectingcontrol cables for the gear hub and/or a rear brake, the mounting of thedrive onto the bicycle can be further facilitated.

It is observed that the invention is by no means is limited to theembodiments described and shown in the description and the Figures. Manyvariations thereof are possible. For instance, the invention is notlimited to a foldable bicycle. The invention may also be advantageouslyapplied to other bicycles with or without a pivotable frame, such as abicycle of which a first part of the frame is spring-connected to asecond part of the frame. Further, the front wheel as well as the rearwheel may be connected to the frame in a conventional manner by means ofa forked supporting construction.

Moreover, the diameters of the wheels may be chosen to be different andthe gear hub and/or the crankshaft may also be accommodated in thesupporting arm. It is also possible that, viewed in the direction oftravel, the gear hub islocated elsewhere, for instance in front of thecrankshaft.

Further, it is possible that the gear hub is integrated with orconcentric with the crankshaft, which, as a matter of fact, may also beadvantageous in respect of other types of bicycles.

These and many other variations are understood to fall within theframework of the invention as expressed in the following claims.

What is claimed is:
 1. A bicycle, comprising a first frame partconnected to a second frame part, said second frame part being providedwith a drive, comprising a crankshaft carrying a driving gear blade anda rear axle carrying a driven gear blade and a gear mechanism forsetting the transmission ratio between the crankshaft and the rear axle,characterized in that the gear mechanism comprises a gear hub having asettable transmission ratio carrying a first, input gear blade coupledto the driving gear blade of the crankshaft and a second, output gearblade coupled to the driven gear blade of the rear axle, such that thetransmission ratio between the first, input gear blade and the second,output gear blade can be set, said gear hub being mounted on the secondframe part at a distance from the rear axle, wherein the drive ismounted on the second frame part as a drive subassembly via a fastenerthrough the second frame part so that the drive subassembly isdetachable as a unit.
 2. A bicycle according to claim 1, wherein thegear hub comprises a first hub part carrying the first, input gear bladeand a second hub part carrying the second, output gear blade.
 3. Abicycle according to claim 2, wherein the hub parts are mounted so as tobe rotatable relative to a support and wherein the support is fixedlyconnected to the second frame part.
 4. A bicycle according to claim 1,wherein the diameter of the first, input gear blade is smaller than thediameter of the second, output gear blade.
 5. A bicycle according toclaim 1, wherein the first, input gear blade and the second, output gearblade are attached to the gear hub adjacent opposite ends thereof.
 6. Abicycle according to claim 1, wherein the gear hub, viewed in sideelevation of the bicycle, is located between an upper common tangentline of the driving gear blade of the crankshaft and the driven gearblade of the rear axle, and a lower common tangent line of the drivinggear blade of the crankshaft and the driven gear blade of the rear axle.7. A bicycle according to claim 1, wherein the gear hub, in direction oftravel of the bicycle, is located between the crankshaft and the rearaxle.
 8. A bicycle according to claim 1, wherein the driving gear bladeof the crankshaft and the first, input gear blade of the gear hub arecoupled by means of a first chain or toothed belt and wherein thesecond, output gear blade of the gear hub and the driven gear blade ofthe rear axle are coupled by means of a second chain or toothed belt. 9.A bicycle according to claim 1, wherein the second frame part comprisesa single supporting arm carrying the rear axle.
 10. A bicycle accordingto claim 1, wherein the first frame part is connected to the secondframe part for pivoting relative to a pivotal axis, such that the frameparts can pivot between an operating position of the bicycle in whichthe wheels of the bicycle are substantially in line, and a foldedposition of the bicycle in which the wheels are substantially locatedside by side.
 11. A bicycle according to claim 1, wherein the connectionbetween the first frame part and the second frame part comprises: alockable hinge for pivoting relative to a substantially vertical axis;and a spring means enabling vertical movement of the first frame partrelative to the second frame part.
 12. A bicycle according to claim 10,wherein the pivotal axis extends substantially vertically.
 13. Thebicycle according to claim 1, wherein the gear hub is mounted on thesecond frame part at a distance from the rear axle.
 14. The bicycleaccording to claim 13 wherein the pedal drive includes a housing whichsurrounds the pedal drive at least partially.
 15. A foldable bicyclecomprising: a first frame part; a second frame part connected to thefirst frame part; a hinge for connecting the first frame part and thesecond frame part and for pivoting the first frame part relative to thesecond frame part about a pivot axis; and a drive mounted to the secondframe part, the drive comprising: a crankshaft carrying a driving gearblade; a rear axle carrying a driven gear blade; and a gear mechanismcoupled between the driving gear blade of the crankshaft and the drivengear blade ofthe rear axle, the gear mechanism having a settabletransmission ratio permitting a rider to set the transmission ratio tovarying speeds between the crankshaft and the rear axle, wherein thedrive is releasably mounted to the second frame part via a fastenerdisposed between the drive and a lower end of the hinge.